Do not strip substrings looking like URL encode sequences
diff --git a/system/database/DB_driver.php b/system/database/DB_driver.php
index e52eb5c..3eb51f7 100644
--- a/system/database/DB_driver.php
+++ b/system/database/DB_driver.php
@@ -1180,7 +1180,7 @@
 	 */
 	protected function _escape_str($str)
 	{
-		return str_replace("'", "''", remove_invisible_characters($str));
+		return str_replace("'", "''", remove_invisible_characters($str, FALSE));
 	}
 
 	// --------------------------------------------------------------------